Viruses Bacteria and Fungus How they affect us

Viruses, Bacteria, and Fungus How they affect us!

What are Viruses • A virus is a tiny, non-cellular, non-living particle that enters and then reproduces inside a living cell. • All viruses have two basic parts: Ø A protein coat that protects the virus Ø An inner core made of genetic material (contains the instructions for making new viruses)

Vary in shapes and sizes These round viruses are responsible for causing West Nile disease in animals. This robotlike virus, called a bacteriophage, infects bacteria.

Once inside the cell, the virus’s genetic material takes over many of the cell’s functions. It instructs the cell to produce the virus’s proteins and genetic material. These proteins and genetic material then assemble into new viruses. • • • Active Viruses 1. A virus attaches to the surface of a bacterium. 2. The virus injects its genetic material into the bacterium. 3. The virus’s genetic material takes over the cell functions of the bacterium. The cell starts to produce the virus’s proteins and genetic material. 4. The proteins and genetic material assemble into new viruses that fill the bacterium. 5. The bacterium bursts open, releasing new viruses. The viruses go on the infect more cells. • • Hidden Viruses 1. A virus attaches to the surface of a bacterium. 2. The virus injects its genetic material into the bacterium. 3. The virus’s genetic material becomes part of the genetic material of the bacterium. 4. After some time, the virus’s genetic material removes itself and becomes active. 5. The cell begins to produce the virus’s proteins and genetic material, which assemble into new viruses. 6. The new viruses crowd the bacterium. Finally, the cell burst open and releases the new viruses.

The Bad and The Good • Viruses and Diseases • Usefulness of Viruses • Mild viral diseases last for short times with quick recovery (colds) • Serious viral diseases have more serious effects on the body (AIDS) • Viruses do not affect only humans but also plants and animals • Apple trees – Apple Mosaic Virus • House pets (dogs and cats) – rabies and distemper • In gene therapy, genetic material is added to a virus to use the virus as a “messenger service” to deliver to affected cells • For example: for the treatment of cystic fibrosis

Bacteria DNA

Anton Van Leeuwenhoek • Discovered bacteria by accident while looking at scrapings from his teeth

Prokaryotic Cells • • Also called bacteria World’s smallest cells No nucleus Circular DNA (shaped like a rubber band) No membrane-covered organelles Contains cytoplasm and ribosomes Some may have a flagellum for movement

Prokaryotes • Cells that do not have a nucleus • Exist almost every where on earth • Grow in numbers so great you can see them with the unaided eye

Bacterium Shapes • Cocci~ Sphere shaped bacteria • Bacillus~ Rod shaped bacteria • Spirrillium ~ Spiral shaped bacteria • Flagella~ Leg-like structures that help to propel the bacterium.

Movement - Bacteria • Flagella ~ Tail like structure the whips around to propel the bacterium

How bacteria eat? Autotrophs Make their own energy Using Solar energy Eg. Cyanobacteria Make own Energy Using Chemical energy Eg. Archaebacteria Heterotrophs Obtain food by eating Eg. E-coli Chemotrophs

Respiration • Bacteria need a constant supply of energy to carry out their functions. • This energy comes from the food they eat. • The process of breaking down food to release energy is called RESPIRATION. • A few bacteria do not need oxygen to break down their food. - anaerobic • Some bacteria die if oxygen is present in their surroundings.

Bacterial Reproduction • Binary Fission • Cellular organism copies it’s genetic information then splits into two identical daughter cells • Asexual reproduction • Conjugation • Two bacteria swap genetic information through a thread-like bridge • Sexual reproduction Sometimes, conditions in the environment become “UNFAVORABLE” for the growth of bacteria. Ex. No food source, too dry, too wet, too hot, too cold Bacteria will form endospores to survive these conditions. An endospore is a small, rounded, thick-walled, resting cell that forms inside the bacterial cell.

Bacterial Relationships Symbiosis Mutualism • Close relationship between two species in which at least one species benefits from the other • Live together for LIFE • Symbiosis in which two of the species live together in such a way that both benefit from the relationship • Eg. E-coli Parasitism • Bacteria exploit the host cell, injuring them

The role of Bacteria in Nature Oxygen Production - Food Production Environmental Cleanup Environmental Recycling Health and Medicine

• Oxygen Production – Autotrophic bacterial use the sun’s energy to produce food with oxygen as a product. • Food Production – Bacteria is used to make vinegar, buttermilk, yogurt, sour cream, and cheeses. (Food is heated enough to kill most harmful bacteria through a process called pasteurization. ) • Environmental Recycling – Decomposers are organisms that break down chemicals on dead organisms into small chemicals. • Environmental Cleanup – Some bacteria help clean up Earth’s land water. Some bacteria prefer to eat oil. They convert the poisonous chemicals in oil into a harmless substance. • Health and Medicine – You have natural bacteria in your stomach to help with digestion. Some help your body make needed vitamins. Others compete for space preventing harmful bacteria from taking up residency. Bacteria is used to make human insulin for diabetic patients.

Nitrogen Fixations • Process by which nitrogen in the atmosphere is converted into a form that can be used by living things by bacteria.

Viruses, Bacteria, and Your Health • Infectious diseases – illnesses passed from one organism to another Ø Can spread through: üContact with an infected person üA contaminated object üInfected animal üAn environmental source

How infectious diseases are spread Infected person – Direct - touching, hugging, kissing Indirect -inhaling drops from a sneeze or cough Contaminated Objects – Sharing eating and drinking objects touching contaminated surfaces Infected Animals – Animal bites Environmental Sources – Food, soil, water

Antibiotic • A chemical that can kill bacteria without harming a person’s cells Antibiotic resistance • When some bacteria are able to survive in the presence of an antibiotic Toxin • A poison that can harm an organism Vaccine • A substance introduced into the body to stimulate the production of chemicals that destroy specific viruses or bacteria

Antibiotics and Bacterial Diseases Lyme Disease Tuberculosis Tetanus Symptoms: rash at bite, chills, fever, body aches, joint swelling Spread: bite from infected tick Treatment: Antibiotic Prevention: Tuck pants into socks; wear long –sleeved shirt Symptoms: fatigue, mild fever. Weight loss, night sweats, cough Spread: Inhaling droplets Treatment: Antibiotic Prevention: Avoid contact with people with active infection: vaccine (for those at high risk) Symptoms: Stiff jaw and neck muscles, spasms, difficulty swallowing Spread: Deep puncture wound Treatment: Antibiotic; opening and cleaning wound Prevention: Vaccine

Antibiotics and Bacterial Diseases Strep Throat Symptoms: Fever, sore throat, swollen glands Food Poisoning Symptoms: vomiting, cramps, diarrhea, fever Spread: Inhaling droplets; contact with a contaminated object Treatment: Antibiotic Prevention: Avoid contact with infected people; do not share utensils, cups, or other objects Spread: Eating food containing the bacteria Treatment: Antitoxin medicines Prevention: properly cook and store foods; avoid eating foods in rusted and swollen cans

Vaccines and Viral Diseases Influenza Symptoms: high fever, sore throat, headache, cough Spread: Contact with contaminated objects; inhaling droplets Treatment: bed rest; fluid Prevention: Vaccine Hepatitis C Symptoms: often no symptoms; jaundice (yellowing of the eyes and skin) fatigue Spread: Contact with blood of an infected person Treatment: Drugs to slow viral multiplication Prevention: Avoid contact with infected blood

Vaccines and Viral Diseases Chicken Pox Symptoms: fever; red, itchy rash Spread: contact with the rash; inhaling droplets Treatment: Antiviral drugs (for adults) Prevention: Vaccine Acquired Immunodeficiency Syndrome (AIDS) Symptoms: weight loss; chronic fatigue; fever; diarrhea; frequent infections Spread: sexual contact; contact with blood; pregnancy, birth, and breastfeeding Treatment: Drugs to slow viral multiplication Prevention: Avoid contact with infected bodily fluids

Fungi • Fungi areØ Eukaryotic cells that have cell walls Ø Heterotrophs that feed by absorbing their food Ø Use spores to reproduce

Size and labeling • Tiny unicellular yeasts • Larger multi-cellular fungi • Largest is an underground fungus as big a 1, 000 football fields • Hyphae – the branching, thread-like tubes that make up the bodies of multicellular fungi.

Although fungi are heterotrophs, they do not take food into their bodies as you do. • Instead, fungi absorb food through hyphae that grow into the food source. • Then, digestive chemicals ooze from the hyphae into the food. • The chemical breaks down the food into particles small enough to be absorbed by the hyphae.

Fungi Reproduction • Fungi usually reproduce by making spores. The lightweight spores are surrounded by a protective covering and can be carried easily through are or water to new sites. • Spores are produced in the fruiting bodies. • Even though fungi produce millions of spores, only a few will land where conditions are right for survival. • Yeast- reproduce by budding

Most fungi reproduce both asexually and sexually. Spores • When there is adequate food and moisture. Budding • A small yeast cell grows from the body of a parent cell and then breaks away and lives on its own. Sexual Reproduction • When growing conditions become unfavorable, the hyphae of two fungi grow together and genetic material is exchanged.

Classification of Fungi Club Fungi – Zygote Fungi – Produce spores Includes: mushrooms and puffballs Produce spores Includes: common fruit and bread molds, such as Rhizopus Sac Fungi – Produces spores Includes: Yeasts, morels, and truffles

Fungus’ Roles in Nature Environmental Recycling Disease Fighting Food Disease. Causing Fungus-Plant Root Association

Disease – Fighting Environmental Recycling • Many are decomposers Fungi and Food • Yeasts help to make bread • We eat mushrooms and truffles Fungi • Penicillium produces a substance that kills bacteria

Lichens Disease – Causing Fungi • Many are parasites • Corn smut and wheat rust destroyed crops • Athlete’s Foot • Ring worms Fungus-Plant Root Association • Symbiotic relationship in which hyphae from a fungus absorbs food and water for the plant • Symbiotic relationship between a fungus and either a bacteria or algae. • Useful indicators of pollution because they are very sensitive and die as pollution levels increase